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https://github.com/bjoerge/debounce-promise
Create a debounced version of a promise returning function
https://github.com/bjoerge/debounce-promise
Last synced: 7 days ago
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Create a debounced version of a promise returning function
- Host: GitHub
- URL: https://github.com/bjoerge/debounce-promise
- Owner: bjoerge
- License: mit
- Created: 2015-10-18T14:13:56.000Z (about 9 years ago)
- Default Branch: master
- Last Pushed: 2023-09-18T12:22:20.000Z (about 1 year ago)
- Last Synced: 2024-11-21T22:30:45.659Z (23 days ago)
- Language: JavaScript
- Size: 67.4 KB
- Stars: 241
- Watchers: 3
- Forks: 27
- Open Issues: 8
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# debounce-promise
[](https://travis-ci.org/bjoerge/debounce-promise)
[](http://standardjs.com/)
[](https://nodei.co/npm/debounce-promise/)
Create a debounced version of a promise returning function
## Install
npm i -S debounce-promise
## Usage example
```js
var debounce = require('debounce-promise')
function expensiveOperation(value) {
return Promise.resolve(value)
}
var saveCycles = debounce(expensiveOperation, 100);
[1, 2, 3, 4].forEach(num => {
return saveCycles('call no #' + num).then(value => {
console.log(value)
})
})
// Will only call expensiveOperation once with argument `4` and print:
//=> call no #4
//=> call no #4
//=> call no #4
//=> call no #4
```
### With leading=true
```js
var debounce = require('debounce-promise')
function expensiveOperation(value) {
return Promise.resolve(value)
}
var saveCycles = debounce(expensiveOperation, 100, {leading: true});
[1, 2, 3, 4].forEach(num => {
return saveCycles('call no #' + num).then(value => {
console.log(value)
})
})
//=> call no #1
//=> call no #4
//=> call no #4
//=> call no #4
```
### With accumulate=true
```js
var debounce = require('debounce-promise')
function squareValues (argTuples) {
return Promise.all(argTuples.map(args => args[0] * args[0]))
}
var square = debounce(squareValues, 100, {accumulate: true});
[1, 2, 3, 4].forEach(num => {
return square(num).then(value => {
console.log(value)
})
})
//=> 1
//=> 4
//=> 9
//=> 16
```
## Api
`debounce(func, [wait=0], [{leading: true|false, accumulate: true|false})`
Returns a debounced version of `func` that delays invoking until after `wait` milliseconds.
Set `leading: true` if you
want to call `func` and return its promise immediately.
Set `accumulate: true` if you want the debounced function to be called with an array of all the arguments received while waiting.
Supports passing a function as the `wait` parameter, which provides a way to lazily or dynamically define a wait timeout.
## Example timeline illustration
```js
function refresh() {
return fetch('/my/api/something')
}
const debounced = debounce(refresh, 100)
```
```
time (ms) -> 0 --- 10 --- 50 --- 100 ---
-----------------------------------------------
debounced() | --- P(1) --- P(1) --- P(1) ---
refresh() | --------------------- P(1) ---
```
```js
const debounced = debounce(refresh, 100, {leading: true})
```
```
time (ms) -> 0 --- 10 --- 50 --- 100 --- 110 ---
--------------------------------------------------------
debounced() | --- P(1) --- P(2) --- P(2) --- P(2) ---
refresh() | --- P(1) --------------------- P(2) ---
```